1. Field of the Invention
The present invention relates to devices used to enclose the capped test ports on a power house precipitator.
2. Description of the Prior Art
As a general background, all boilers and other types of power house precipitators include at least one stack or test port through which to inspect the condition of the precipitator. Substantial amounts of moisture and fly ash circulate inside such precipitators and solidify on the inside walls of the test ports. The buildup of this ash is often so great that it is almost impossible to remove from the surface of the inside walls of the ports.
The Environmental Protection Agency (hereinafter referred to as EPA) presently requires that an inspection be made of these test ports every six months. To facilitate this inspection, it is necessary to install some kind of removable cover over the projecting collar or end of these test ports. It is the present state of the art to place a removable metal cover or cap over the test port opening between the six-month inspections. This cap may be secured to the end of the port by any number of conventional means, such as by threading the port and cap or by plugging the cap into an appropriately sized pipe coupling.
However, such metal coverings cause much problem because the buildup of fly ash often "cements" the cover to the test port thereby making it impossible to remove the cover from the opening in order to conduct the inspection. It is believed that this "cementing" action results at least in part from the temperature difference between the hot ash and water vapor circulating inside the port and the much cooler outside air. This gradient causes the ash to solidify on the inside wall of the port and almost weld the cap in place. It is not unusual in such situations to require a blow torch to remove the "cemented" cover.